The 350 ‘almost’?… shoulda been a real 35 (357-358), not a 9mm. That turned me against it from the jump, as the 357 AR work had been done. As I already have 6.8 SPC stuff, the 400 makes more sense….especially if you want to suppress…..it’s all short range anyway, so why not? Stronger bolts than bushmasters, less recoil, and seems to have more juice and possibilities than the .355. Maybe not, but we shall see.